1. Field of the Invention
The present invention relates to an interior cooling structure which incorporates multiple circuit boards and, in particular, to an ultrasound imaging apparatus equipped with the interior cooling structure and connected to an ultrasound endoscope.
2. Description of the Related Art
In recent years, an ultrasound diagnostic method has spread widely. The ultrasound diagnostic method makes a diagnosis by emitting ultrasound into a body cavity and producing images of body conditions based on echo signals from the body cavity. Medical apparatus used for such ultrasound diagnostic method include, for example, an ultrasound echo apparatus which can produce images of conditions inside the body from the surface of the body and an ultrasound endoscope which includes, in its distal end portion, an ultrasound vibration unit that transmits/receives ultrasound can produce images of conditions inside the body by being inserted into a body cavity.
The ultrasound endoscope is connected with an ultrasound imaging apparatus (also called an ultrasound diagnostic apparatus) such as described, for example, in Japanese Patent Application Laid-Open Publication No. 2001-340337, where the ultrasound imaging apparatus is a medical apparatus which converts echo signals into images. As is well known, the ultrasound imaging apparatus contains multiple electronic components in a box-shaped housing. The housing contains multiple boards with various electronic components classified according to functional configuration of circuits.
Normally, a radiator fan (blower) and exhaust fan are installed in the apparatus housing to reduce temperature rises in the apparatus caused by heat produced by the electronic components mounted on the boards. Cooling configurations for use to reduce such temperature rises in apparatus are proposed, for example, in Japanese Patent Application Laid-Open Publication Nos. 2006-20755 and 2006-202869.
Japanese Patent Application Laid-Open Publication No. 2006-20755 discloses a technique for a portable medical apparatus which circulates air in the apparatus using an exhaust fan to cool the apparatus without the need for forced exhaust from the apparatus.
On the other hand, Japanese Patent Application Laid-Open Publication No. 2006-202869 discloses a technique for a box-shaped apparatus which eliminates the need for an exhaust fan by distributing louvers along the width of an exhaust passage of cooling air from multiple blowers with the longitudinal direction of each louver turned a predetermined angle to control exhaust directions of the cooling air.